Python中exit()和sys.exit()之间的区别 [英] Difference between exit() and sys.exit() in Python

问题描述

在Python中，有两个名称相似的函数exit()和sys.exit().有什么区别，什么时候应该在另一个上使用?

In Python, there are two similarly-named functions, exit() and sys.exit(). What's the difference and when should I use one over the other?

推荐答案

exit 是交互式外壳程序的帮助程序- sys.exit 是用于程序.

exit is a helper for the interactive shell - sys.exit is intended for use in programs.

site 模块(在启动过程中自动导入，除非提供了 -S 命令行选项)内置命名空间(例如exit). 它们对于交互式解释器外壳很有用，不应在程序中使用.

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从技术上讲，它们的作用大致相同:提高 SystemExit . sys.exit在 sysmodule.c :

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Technically, they do mostly the same: raising SystemExit. sys.exit does so in sysmodule.c:

static PyObject *
sys_exit(PyObject *self, PyObject *args)
{
    PyObject *exit_code = 0;
    if (!PyArg_UnpackTuple(args, "exit", 0, 1, &exit_code))
        return NULL;
    /* Raise SystemExit so callers may catch it or clean up. */
    PyErr_SetObject(PyExc_SystemExit, exit_code);
   return NULL;
}

exit是在 site.py中定义的和 _sitebuiltins.py ，分别.

class Quitter(object):
    def __init__(self, name):
        self.name = name
    def __repr__(self):
        return 'Use %s() or %s to exit' % (self.name, eof)
    def __call__(self, code=None):
        # Shells like IDLE catch the SystemExit, but listen when their
        # stdin wrapper is closed.
        try:
            sys.stdin.close()
        except:
            pass
        raise SystemExit(code)
__builtin__.quit = Quitter('quit')
__builtin__.exit = Quitter('exit')

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请注意，还有第三个退出选项，即 os._exit ，它将退出而无需调用清理处理程序，刷新stdio缓冲区等(并且通常只应在fork()之后的子进程中使用).

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Note that there is a third exit option, namely os._exit, which exits without calling cleanup handlers, flushing stdio buffers, etc. (and which should normally only be used in the child process after a fork()).

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